If you don’t mind running the workflow yourself you could write the content of the clipboard to a temporary location, and check if it’s still the same the next time you run it.
This would require you to run the shortcut every minute, but since I don’t know your use case… I don’t know, maybe this is actually fine for your situation.
Here’s an example using a file in iCloud drive: https://www.icloud.com/shortcuts/4f8ca28c3d4245c4b5b067ef14d8aa1b